Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ) and represents a major clinical challenge due to its chronicity and impact on quality of life. Current treatments for acute HZ pain have limited efficacy in preventing PHN, highlighting the need for effective preventive strategies targeting early pathophysiological mechanisms. Venlafaxine as a plausible and clinically relevant candidate for early intervention to prevent the transition from acute HZ pain to PHN.
1. Ages more than 18 years;
2. Patients with onset of HZ rash less than 30 days;
3. Experiencing moderate to severe HZ pain with an average pain score of at least 4 on a Numeric Rating Scale (NRS, 0 = no pain, 10 = worst possible pain);
4. Aspartate aminotransferase and alanine aminotransferase levels less than twice the upper limit of normal;
1. HZ with head, neck, ocular, mucous membrane, cranial nerve, or central nervous system involvement or generalized HZ;
2.Known hypersensitivity to venlafaxine;
3. Previous antiviral treatment that did not comply with guideline recommendations;
4. History of herpes zoster vaccination before enrollment;
Parallel
Venlafaxine combined conventional therapy
DrugVenlafaxine will be initiated at 75 mg once daily and titrated based on pain response and tolerability before 90 days after rash onset. All participants will receive standardized analgesic management following the World Health Organization pain ladder. In addition, the group will contain conventional treatment for HZ, including NSAIDs, opioids, antiviral drugs and so on. After 90 days from rash onset, treatment will be standardized across both groups. Participants who develop persistent pain consistent with PHN will receive guideline-based management, including gabapentinoids, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and topical agents such as lidocaine or capsaicin, as clinically indicated.
Conventional therapy
DrugThe control group will receive conventional therapy alone before 90 days after rash onset. After 90 days from rash onset, treatment will be standardized across both groups. Participants who develop persistent pain consistent with PHN will receive guideline-based management, including gabapentinoids, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and topical agents such as lidocaine or capsaicin, as clinically indicated.
Incidence of PHN
PHN will be defined as persistent pain in the affected dermatome at 90 days after rash onset that is clinically meaningful, operationalized as an average pain score ≥ 3 on the NRS.
The average daily pain intensity
The numeric rating scale (NRS) score is a way to quantify the degree of subjective feelings such as pain using numbers. Generally, 0 represents no pain, and 10 represents the most severe pain. A higher score indicates more severe pain.
The worst numeric rating scale score
The numeric rating scale (NRS) score is a way to quantify the degree of subjective feelings such as pain using numbers. Generally, 0 represents no pain, and 10 represents the most severe pain. A higher score indicates more severe pain.
Proportion of Patients Achieving Pain Reduction
The proportion of patients achieving a ≥ 50% and ≥ 30% reduction in mean baseline pain intensity
Average weekly consumption of each analgesic class
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Beijing Tiantan Hospital
Lead sponsor
Xiangya Hospital of Central South University
Collaborator
Zhongnan Hospital
Collaborator
Jilin Provincial People's Hospital
Collaborator
